I have this code snippet
import asyncio
import time
async def put_stuff_into_queue(stuff_into_queue: list[str], queue: asyncio.Queue) -> None:
for stuff in stuff_into_queue:
await queue.put(stuff)
await asyncio.sleep(1)
print(f"end time: {time.strftime('%X')}")
async def process_stuff_from_queue(queue: asyncio.Queue) -> None:
while True:
stuff: str = await queue.get()
print(stuff)
async def main() -> None:
queue = asyncio.Queue()
stuff_into_queue = ["this", "is", "a", "simple", "test"]
print(f"start time: {time.strftime('%X')}")
asyncio.create_task(put_stuff_into_queue(stuff_into_queue, queue)) # this line is never awaited
asyncio.create_task(process_stuff_from_queue(queue)) # this line is never awaited
await asyncio.sleep(8) # with this line, the previous two lines seems to be running
# time.sleep(8) # if I comment out the previous line and instead use this line, then all the tasks don't run
if __name__ == '__main__':
asyncio.run(main())
The output I receive with the code as it is above is
start time: 15:54:38
this
is
a
simple
test
end time: 15:54:43
Process finished with exit code 0
If I run with time.sleep(8) instead of await asyncio.sleep(8), then my output is
start time: 15:59:09
this
Process finished with exit code 0
The console output this occurs after sleeping for 8 seconds, so I presume it has something to with the unawaited tasks executing a single iteration once asyncio.run(main()) is done? I am not entirely sure why I only get one iteration, or why I even get an iteration of Task event loop.
Why are the two un-awaited tasks running perfectly when I have await asyncio.sleep(8), but not when I have time.sleep(8)? Does it have something to do with GIL when doing time.sleep where it somehow blocks the main loop flow?
Why are the two un-awaited tasks running perfectly when I have await asyncio.sleep(8), but not when I have time.sleep(8)?
Because that's how asyncio works: calling await is what yields execution back to the scheduler so that it can run other async tasks. When you call time.sleep, you're never calling await, so other async tasks never get the chance to run.